


concubitus

by WhyArentIBlessd



Series: From the Devildom [1]
Category: Shall We Date?: Obey Me, Shall We Date?: Obey Me!
Genre: Beelzebub isn't a Complete Fool, Budding Love, Canon Rewrite, Domestic Fluff, F/M, Gen, Hinted cohabitation, M/M, Mammon has feelings by yelling, Mild Hurt/Comfort, Multi, POV Second Person, Platonic Cuddling, Reader is never gendered, Reader-Insert, Shitty First Aid Trope, Sleepy Cuddles, gender neutral reader
Language: English
Status: Completed
Published: 2019-12-22
Updated: 2019-12-23
Packaged: 2021-02-25 23:08:13
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,390
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21903487
Author URL: https://archiveofourown.org/users/WhyArentIBlessd/pseuds/WhyArentIBlessd
Summary: (n) 'concubitus'Definitions:- lying together, reclining together (sleeping/dining/sex)- sexual intercourse, coitusconnected to:(n) cohabitationthe state or fact of living or existing at the same time or in the same place."a harmonious cohabitation with other living creatures"
Relationships: Beelzebub (Shall We Date?: Obey Me!)/Reader, Beelzebub/Mammon (Shall We Date?: Obey Me!)/Reader, Main Character/Mammon (Shall We Date?: Obey Me!)
Series: From the Devildom [1]
Series URL: https://archiveofourown.org/series/1579723
Comments: 58
Kudos: 838





	1. Chapter 1

**Author's Note:**

> For reference, while these stories are gathered together in a ‘series’, they in no way have any relation to one another. Each MC is meant to be unique and different, as is their relationships to the brothers. I have sorted them into a series more to keep them gathered together rather than because they are in any way connected. There is no continuity between stories or MCs, aside from anything explicitly stated or canonic events. Sorry for any confusion!

While you wanted to know what was at the top of the spiral staircase, Leviathan’s rage was more than you were prepared for. You had expected his resistance, especially considering his freedom was on the line now that you’d bet a pact on the quiz, but seeing him… change that way, it scared you. Lucifer and Diavolo had always toed the fine line between ‘You’re completely safe under our watch’ and ‘Facing a demon on your own is impossible’, and Mammon was even less confident in your safety on your own. Run, or die- those were his options, weren’t they?

Your eyes widened as Leviathan’s horns and tail seemed to materialize, not quite sprouting from his human form but not quite appearing out of nowhere. It was like they took their rightful places, making him a complete picture now more than ever. If your life weren’t in danger, maybe it would’ve been awe-inspiring to see the reclusive third-born come into his power and might this way. Instead, you retreated a little, stumbling as you realized he was coming for _you_ directly, and you cried out before you could even really decide what to do. Run or die? Run or die? Run or-

“MAMMON, HELP!” Glancing back over your shoulder, eyes wide, you made a fatal mistake as your balance shifted and you went down.

“Hold on! I’m comin’…” You floundered as Mammon sent relief through you, hitting the floor palm first with a sharp pain, but your eyes went to Levi next as he advanced, squeezing the air out of your lungs. Leviathan was harmless, all bark and no bite- he could hardly string insults together besides the typical ones that _everyone_ used for Mammon. Besides, speaking of Mammon, he was-

“Beel, you idiot! What’s the big idea drippin’ ice cream all over the floor?! You made me slip!” He slipped? You turned back to look at him again, that relief you’d tripped over locking you up in shock, and true to his scolding, Mammon was on the floor too. “Dammit, I’m not gonna make it in time…!” The look in his eyes was serious, even panicked, and you couldn’t even look back at Levi. The crushing feeling of his anger was enough to let you know how close he was, and you couldn’t look. You squeezed your eyes shut instead, dread making it feel like your limbs were glued to the floor, and you did all you really could do.

Run or die.

But- “…thats enough.” -the gravelly, resounding voice of Lucifer set a chill through the whole room, different from his usual reserved tone. “I believe you were going to settle this via a QUIZ, weren’t you? Not through violence. You’re out of control, Levi.” Leviathan stopped, the oppressive force that was his rage coming to an almost complete halt, and you couldn’t help but peek at the eldest brother tentatively.

Everyone looked stunned, Mammon’s lips a tight line as he got up from the floor slowly, eyes trained on his older brother.

“Unbelievable!” Asmodeus had no qualms with breaking the tension, glancing at Satan next to him as everyone seemed to wait on baited breath. “Just as Leviathan was about to strike who should step in and stop him but the one and only Lucifer himself! Simply incredible!” And simply incredible was right.

He was another sight to behold, seemingly unleashed as his younger brother had been but entirely different. Lucifer was fearsome and radiant, a cold expression on his face like one you’d never seen before, and the horns on his head framed his forehead like a crown. You could understand all the references to Lucifer in the Bible now, humans calling him the most glorious of all the angels, and as he turned from Leviathan to look down at you, the four wings that seemed so _right_ there behind his broad shoulders shifted minutely with him. Numbly, you scolded yourself because why wouldn’t his wings move with him.

“I haven’t seen you leap to someone’s rescue like that in quite some time, Lucifer.” Satan easily took you out of the spotlight, making Lucifer look away as you got to your feet and cradled your throbbing wrist. It was a blessing and a curse, his gaze as piercing as a shard of pure garnet, and you shot an uncertain look to Mammon now as you admittedly retreated back to stand with the other brothers. Leviathan was a wild card and Lucifer, while currently defending you, was as unsettling as he was beautiful.

He took charge immediately, ordering Leviathan away and questioning Mammon, and everything seemed to settle down and slip out of your view in a blink. His wings shuffled and seemed to fold out of existence instead of just behind his back, disappearing, and his horns went missing as his wings preoccupied your curious eyes. Mammon was surprisingly silent, usually the gregarious one with no sense of timing, but he was just scowling and lingering at your side as Leviathan left and everyone else relaxed.

Asmodeus and Satan were unconcerned, more than happy to tease their older brothers about coming to and failing to come to your defense, and Beelzebub was unaffected, snacking away comfortably as the family converged around you momentarily. You were fine, after you had a few moments to recover from the shock of the incident, and your wrist was only sprained a bit from falling wrong. You could handle it, especially if Mammon was going to hover and glower at you like this, so you happily bid them goodnight to retreat to your bedroom. Beelzebub tagged along, tasked by Lucifer as he took Diavolo aside and his other brothers happily skirted the responsibility.


	2. Chapter 2

**Notes for the Chapter:**

> Mystery guest who left kudos... I love you.

When you returned to your room, however, you were surprised that the towering Avatar of Gluttony decided to stay. He drifted in and out, returning with pizza as Mammon tore the room apart, but you were glad for the more peaceful company. Mammon had set right into you about the whole thing as soon as you all returned, shoving your shoulder to force you to sit down on your bed, and you winced slightly as he leapt right into a tirade. The last thing you really needed, but you were having a hard time trying to find a place to interject. It just didn’t seem right to use your pact for this when it was something so petty.

“So, ya made it out of that without being attacked, only to end up fallin’ on your butt and sprainin’ your wrist… seriously, could you be any more of a klutz?” He grumbled, rooting around in the small adjoined bathroom. You could hear him throwing things aside as he failed to find… whatever he was looking for, and you could already see the mess in your mind. Beel at least offered you a bite or two as you sat there, one hand aching as the swelling set in, while Mammon tore apart your bathroom.

“You humans really are way less physically capable than us demons.” Hummed the ginger-haired demon, drawing your attention from the mess as Mammon came striding out with what had to be a first aid kit. The script and symbol on it were foreign, but he tore out familiar equipment and supplies as Beelzebub stretched out a massive hand to inspect your wrist. “That’s because you don’t eat enough. And unlike us, you don’t eat the right things.”

“Stop tying everything” -Mammon paused to tear a wrapper with his teeth, snappy.- “back to food, Beel! Actually, why’re you even here, anyway? Seems to me that you’ve been spendin’ an _awful_ lot of time here ever since the night of the DVD marathon…” He fixed him with a suspicious look, eyes narrowing behind his tinted sunglasses as he flicked his wrist and unrolled a long roll of bandage. If you weren’t reading too much from his glare, you could have sworn he was trying to banish him with his eyes alone.

“Well,” Beel chewed thoughtfully for a moment, unaffected. “so have you.” Mammon scoffed at the statement, but Beel shook his head slightly and added: “I mean, you’ve even left a cell phone charger here. And a toothbrush, too. That’s how much you’re over here.”

“W…well that’s because, uh…you know…I’ve gotta look after this human, don’t I? it’s my job…”

You had to admit that you were a little shocked yourself, hearing Beelzebub point it out as the two brothers bickered, and you wondered how you’d let Mammon and Beelzebub get so comfortable in your room. Weren’t you supposed to be taking Luke’s advice and being cautious of the demons, especially one who would sell you out in their pursuit of ‘all the money in the world’? Shouldn’t you be frightened of Beelzebub, the brother everyone was sure would eat you if he was left in charge of your safety?

“Mammon, you’re doing a terrible job with those bandages.” Beelzebub pointed out as Mammon trailed off, trying to justify his own increasing presence in your rooms.

“Hey, shut up!” Mammon barked, scowling at him. “I’ve never had to wrap someone’s wrist before, okay? I don’t know how it works!” Letting go, he waved his hands at it goadingly as he rose to his full height and abandoned the task. “If you think I’m doin’ such a bad job, then why don’t _you_ do it, Beel!”

However, his younger brother was pleasantly engrossed in his eternal meal. He had eaten through most of the pizza alone, aside from the two pieces you had been delegated and those Mammon had laid claim to, and he was moving into Mammon’s share without concern. However, he was aware of _Mammon_ noticing and he wad glad to rise with a glance at you and make an excuse.

“You know, I could really go for soda right now.” He said conversationally, seeming to segue poorly away from Mammon’s shouting. “I’m going to go run to the kitchen.” He didn’t mind that Mammon was calling after him, or cursing him, and Mammon threw a packet of bandages after him as he closed the door to the hall. He was huffing, frustrated, and he just ruffled his hair before he turned back to you and your sprained, bandage draped wrist. You shrugged, trying to contain laughter, and he just scoffed before he took the bandage back to restart.

“Of all the… Seriously, does that guy ever stop eatin’?!” He grumbled, working more carefully this time as he wrapped your wrist in bandage again. He shot your pizza slices a dirty look too, as if they were to blame. “You’d better keep a close eye on your pizza, or he’ll steal yours away next.”

“I think I can stand to let him have it. He’s the one who’s supposedly going to eat me, remember?” You countered, teasing him gently as he seemed to get the hang of first aid. He was wrapping it more tightly than before, making up for his untidy first aid job with it’s effectiveness. You were surprised he could do things like this as a demon, when he was so hard to damage himself, but you were grateful for the help. You doubted you could have tied it properly on your own. “Thank you for this, by the way. I see now why Lucifer made you my escort. You’re coming in pretty handy.” And you wiggled your fingers, hoping to get even a groan out of the irritable demon.

Instead, he surprised you.  
“...Ah…um, by the way… There’s somethin’ I want you to know.” Mammon muttered, eyes down on his task as he shifted the bandages about and tried to straighten up his handiwork.

“What, do I owe you grimm for this? How much? One thousand, ten thousand?” You asked slyly, letting him fidget with your wrist until you had to twist the screw. It wasn’t often that you got to see Mammon squirm, not like this, and you had to wonder if this is how Lucifer felt when he teased him. It was more fun than you’d first expected; maybe you could make a habit of it.

“...Listen.” Mammon caught your hand in a firm grip as you moved to pull it away, and he met your stare now seriously. It pulled the smile from your face, surprised and a little sore in his grasp, and you swallowed. “The next time your life’s in danger, I’m gonna be the one to save you, all right? Don’t you forget that. And… if I can’t manage to save ya…”

“Wh-” You were stunned, hearing him speak, and you waited a second for him to reveal the punchline. “Mammon… I-”

“Then make sure you die, got it?! I don’t want no one else steppin’ in and savin’ you, all right?!” He growled, grip stern as he kept your hand and your attention locked on him. “It’s me or no one, understand?!” It wasn’t the sweetest thing someone had ever said to you, or the most heartfelt confession anyone had given, but it was most certainly very, _very_ Mammon, and it made you smile before you could help it.

He stood up and dropped your hand, as if he wasn’t tense and waiting for some response from you, so you sat back on your good hand and relaxed. “All right, got it.” Admittedly, today had almost gone the same way. You’d been so sure Mammon would make it, just like in the movies, and if not for Lucifer, Levi would surely have taken off your head. “I’m looking forward to being saved by you.”

Mammon blushed at the response, flustered, and he snorted as he turned to shove the rest of the supplies haphazardly into the kit again. “G-Good, jeez…” He muttered as you watched the embarrassment colour the tops of his ears. “you should always just agree with me like that.”

“It’s usually more fun to play difficult.” You admitted, shrugging when he whirled to scowl at you. “I just couldn’t refuse such a heartfelt, greedy request… from my one and only hero, at that.”

Mammon looked ready to explode as you teased him again, feeling a smile pull your lips upwards even more, but then you heard a familiar tinkling and your amusement was forgotten.

“Huh…? That ain’t my phone.” Mammon grumbled, pulling out his device before he raised an eyebrow at you. “Hey… your D.D.D.’s ringing.”


	3. Chapter 3

You pulled out your D.D.D. in surprise as it kept ringing, the sound cutting through the usual peace present at this time of night. As far as you knew, everyone else was heading to bed now that the midnight quiz was over. You’d never had anyone but Mammon or a misdial call you this late, though some of the brothers made you ask yourself if they were _really_ calling the wrong number. Satan, in particular, but he was another story.

“It’s Beelzebub,” You offered in explanation, taking the call and pressing it to your ear without hesitation. Mammon was complaining already, your attention diverted, but your focus on his younger brother drowned him out mostly. “Beel, what’s up? Trying to order pizza?” It wouldn’t be the first time he’d mixed up your D.D.D. number with the local delivery place.

“No,” Beelzebub’s voice sounded even deeper through the tiny speaker, something that might have intimidated you if he wasn’t so calm all the time. “I’m at the fridge. I ate more, but I didn’t ask which soda you wanted. Levi has some of his electric green limited edition soda, and there’s Devil Cola, or the Soul Up Asmodeus buys.” You could hear him hold the device away and take a bite of something that shattered similar to a dinner plate, but you didn’t interrogate him about it.

“Whatever you’re having. I don’t think I need to agitate Levi any more than I already have.” You offered, turning your head a little to scan down Mammon’s back. He was still complaining to himself, but he was messing around with the TV and you had a feeling you weren’t going right to sleep. “Mammon will take Devil Cola, I think, but you’d better hurry. He’s putting something in the player.” You couldn’t take any more TSL right now, but you weren’t going to turn down the chance to get into a little more Devildom pop culture.

With a grunt of acknowledgement, Beelzebub assured you he’d be back soon and ended the call. You could hear more things being opened, so you wouldn’t hold him to it, but it made you smile none the less. He didn’t need to come back, not when he had a black hole in his belly to fill, but he was growing to be as common of a visitor as Mammon. They were both right… they spent a lot more time with you than you’d realized, now that you thought about it.

You woke up to Mammon hogging your blankets all the time, shoving you against the wall or off the edge as he was greedy even in his sleep. He had his charger near the edge so that he could shop, and he made it a mission to assert dominance over his ‘spot’. Beelzebub wasn’t as assuming as he was all encompassing. Due to build alone, Beelzebub had a habit of encroaching on your space without realizing it, until you’re squished against one side or finding yourself squeezed between the two brothers. He was as docile as a lamb whenever you pointed it out, correcting himself, but it was like pushing a rock uphill. Inevitably, he would be pressing against you again, bulk relaxed, and it was hard to scold him for it.

When Mammon came back to the bed, he shooed you aside to get comfortable and you shuffled your legs over slightly before you warned him.

“Leave room for Beel, he’s coming back with drinks.” You commanded, pointing out your last slice without appetite. “You can even have my slice. After Levi, I’m not hungry.” You didn’t need to deal with a brotherly squabble here too.

“Listen, human,” Mammon scoffed, throwing himself down front of you and draping his upper half back against you. He turned you into a comfortable chair backing, head expectantly leaned back against your stomach, and he scowled up at you from below. “if you think I’m gonna just roll over and play nice for you, you’ve got another thing comin’. Just because you can use your pact against me doesn’t mean shit. If you want Beel to have room, you’ve gotta work for it. D’you know how stressful it is takin’ care a you?”

His motions may have been fairly brash, but Mammon reached up confidently for your hands and set your good one in his hair while he held the other hostage against his collarbone.

“An’ I’m keepin’ this before you do somethin’ stupid and wreck all my hard work.” He grunted, squeezing your fingers a little as if you give your sore wrist a break. He was gruff about it, in typical Mammon fashion, but the weight of him laying back onto your lap and stomach was almost reassuring.

“Right, sorry.” You murmured smugly, feeling Mammon’s impatience as he waited for the hand in his hair to do… anything. “Thank you for all your hard work, Mammon.” You let him wait just a little after he hit play to start petting your fingers through his hair lazily, finding your own rhythm as you settled into your evening of indentured servitude, and luckily, Beelzebub wasn’t too much longer.

“Beel, hey, we saved you a spot.” You greeted him distractedly, the hair petting hand patting the half of the bed beside you. “Come sit, Mammon is showing me a different show.” And a welcome distraction from the drama of today.

It took a little maneuvering to help Beelzebub climb over the two of you monopolizing the edge of the bed, but he was finally in his place again and he had the pizza _and_ the sodas you’d asked for.

“Thanks, Beel,” You glanced back in the dark of the bedroom at him, his face illuminated by the TV, but he had an unreasonable expression that made your hair petting pause a little. “Did you find something to eat?”

“Hey, hey, _hey_!” Mammon interrupted bluntly. “Your ‘one and only hero’ here needs more attention! I work myself to the bone for you and _this_ is the thanks I get? Human, you _suck_ at this!” He tugged on your fingers a little, trying to prompt you, and you hurried to resume your actions as you tried to raise your eyebrows at Beelzebub. He looked like he was thinking too hard for someone so carefree, but he didn’t say anything. He had the rest of the pizza to finish, Mammon appeased by your attention, and you just enjoyed your soda as the show played on, concern lingering in the back of your mind. You had no idea how long this series was supposed to be, but you were in for a long haul with the way the two brothers framed you into your own bed.

By the time the disc Mammon chose was winding down to its last episode, you could feel yourself nodding off again and again. Your attention was fading, lulled into state of relaxation by the heavy, warm demon brother using you as a backrest, and even Beelzebub settled against your side wasn’t uncomfortable. Your adrenaline was gone, no longer keeping you alert and worried about the third brother, and you were quickly losing track of the show you were supposed to be watching.

Were they starting the episode or ending it? It was so hard to concentrate when you were so comfortable…

When you jerked awake again, Mammon was moving and you were surprised to feel the cool air take his place. Hands lifted in confusion, hesitating to pull back in case he was just adjusting, you knew your confused frown was the reason he laughed at you and your wrinkled your nose at him groggily.

“Hey human, stop hogging all the space.” He snorted, not one to talk, and he pushed himself back into your space face to face this time. “We’re tired too and you haven’t even been payin’ attention. Here I am, showin’ ya this show outta the goodness of my heart and…” You frankly stopped listening, groggy. He and Beelzebub had herded you away from the edge of the bed some, maybe while you were drifting in and out of sleep, and as he settled against you, Mammon just tucked his head into your shoulder like he had all the right to it in the world. You couldn’t really complain, since it left your wrist free to rest against the pillows, but you grumbled and shifted onto your side a little more to get just comfortable enough. “God, you’re so much better when you don’t talk back.” He hummed.

“Mammon, it’s time to sleep.” Beelzebub’s sudden baritone would have been frightening to most, his silent presence otherwise very easy to miss, but his hands found you tensely before you spoke. They had to be easily as big as dinner plates, the way they hesitated on your sides for a moment, but he filled the space behind you immediately as the two demons seemed to agree on the idea of curling up together. You arched to one side and coaxed his arm beneath you, trying to entangle him in the pile lazily, and the little silent permission seemed to give the go ahead for both big arms to settle around you as Mammon turned you into his favourite body pillow.

It shouldn’t have been as comfortable as it was, easily settling your ruffled feathers about being moved, and you were pleased to find both of them fit comfortably on the bed you’d been provided. Mammon’s breath stirred your shirt, his forehead resting on your collarbone as he seemed to make the most of the attention, and you could feel Beelzebub’s breath tickle the back of your ear as he buried his face in your hair. You could’ve sworn he was more awake than either of you, one hand seeming to size you up between his palm and the bed, and you’re pulse thumped one hard note as you remembered an article about snakes lining themselves up with humans to eat them.

No, this was Beel, not a snake, he-

“Humans… really are way smaller too.” He didn’t seem like he was talking to you either, his voice lower and huskier as he got tired, and you stayed still as you felt him size you up one more time. So he _was_ sizing you up. The deep exhale reminded you more of his older brothers, the deep ‘hhhh’ through the nose that signaled disappointment, and you felt his big hand relax and wrap around your hip as the rest of his bulk settled against you more. “I’ll feed you more good things in the morning. You need to be more careful.”

He went quiet after that, body relaxing into you as the three of you committed to the tangle of limbs, but it seemed like now you were the only one who was wide awake. You could feel the heat creeping up your neck, mortified to have been afraid and embarrassed by Beelzebub’s private concern. True, you weren’t a mountain of a man or the hidden lethality of Lucifer or Simeon, but Asmodeus was slight and diminutive without lacking. You could still feel him tracing you, the concern as he proportioned you out and deemed you to be at risk, and you couldn’t help how it made your face red. Beelzebub wasn’t like Mammon with his affection, the greedy demon an open book to read if you knew the language, and it was sweet above all else to hear him worry.

Closing your eyes, trying to banish your embarrassment, you told yourself you would give them both less reasons to worry when you all woke up, and you wrapped your sore arm around Mammon gingerly as your other hand gently rested over the one Beelzebub had set on your belly.

For now, though, you would just enjoy the tender moment their worrying had created.


End file.
